This invention relates generally to semiconductor lasers and more particularly to such a laser which can be used as a light source suitable for optical communication using multiwavelength light signal.
Conventional trunk circuit amplifiers for multiwavelength light signal splits signal light, which is formed by multiplexing n carrier waves each having different wavelength from another, into an n beams so that respective photodetectors are used to receive different wavelength light rays thereby electrically amplifying to convert into light of different wavelengths. As a result, entire structure is complex, and when increasing the degree of multiplex, scale of junction becomes larger and larger increasing the number of parts which would result in the deterioration in reliability. Furthermore, in order to reproduce light, which has been modulated at a very high speed, it is necessary that characteristics of respective semiconductor devices and electric parts and all the high frequency characteristics are satisfactory. This would result in increase in cost.